The film will be directed by Brett Morgen, who helmed Rolling Stones documentary Crossfire Hurricane.
[Left: Cobain / Right: Cobain's widow Courtney Love]
Morgen said of the Cobain documentary: "It'll be an embodiment of his character. If you think about Kurt, he's a contradiction. He could be sincere and sentimental, and also ironic and sarcastic.
"He was sweet and sour. He was incredibly funny too. The film has to reflect his spirit."
Morgen has been working with Cobain's widow Courtney Love on the project for the past five years and has hinted at a 2014 release date.
His other music documentary Crossfire Hurricane is out on DVD tomorrow (January 7).
Watch Nirvana perform 'The Man Who Sold the World' below: